Outer and inner cowl-wire wrap to one piece cowl conversion

Abstract

A method facilitates replacing a portion of a gas turbine engine combustor. The combustor includes a combustor liner and a wire-wrapped cowl assembly that includes an inner cowl and an outer cowl. The method comprises cutting through the wire-wrapped cowl assembly upstream from fastener openings used to couple the inner and outer cowls to the combustor liner, removing a portion of the cowl assembly from the combustor, and coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cut, wherein the replacement cowl includes an inner annular portion, an outer annular portion, and a plurality of circumferentially-spaced radial ligaments extending therebetween.

What is claimed is:  
     
       1. A method for replacing a portion of a gas turbine engine combustor, the combustor including a combustor liner and a wire-wrapped cowl assembly that includes an inner cowl and an outer cowl, said method comprising: 
       cutting through the wire-wrapped cowl assembly upstream from fastener openings used to couple the inner and outer cowls to the combustor liner;  
       removing a portion of the cowl assembly from the combustor; and  
       coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cut, wherein the replacement cowl includes an inner annular portion, an outer annular portion, and a plurality of circumferentially-spaced radial ligaments extending therebetween.  
     
     
       2. A method in accordance with  claim 1  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cut comprises using at least one of laser welding and brazing to couple the replacement cowl to the existing cowl assembly. 
     
     
       3. A method in accordance with  claim 1  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cut comprises selecting a number of circumferentially-spaced radial ligaments to facilitate a pre-desired natural frequency during engine operations. 
     
     
       4. A method in accordance with  claim 1  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cut comprises selecting a number of circumferentially-spaced radial ligaments to facilitate reducing high cycle fatigue induced to the combustor. 
     
     
       5. A method in accordance with  claim 1  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cut comprises spacing adjacent radial ligaments at a pre-desired length to enable at least one fuel nozzle to be inserted between adjacent radial ligaments. 
     
     
       6. A method in accordance with  claim 1  wherein cutting through the wire-wrapped cowl assembly comprises cutting through the wire-wrapped cowl assembly such that all of the wire-wrapped portion of the existing combustor cowl assembly is removable from the combustor. 
     
     
       7. A method for replacing a portion of a gas turbine engine combustor, the combustor including a combustor liner and a wire-wrapped cowl assembly that includes an inner cowl and an outer cowl, said method comprising: 
       uncoupling the cowl assembly from the combustor liner;  
       cutting between an outer surface and an inner surface of the outer cowl, wherein the cut is formed upstream from a plurality of fastener openings formed within the outer cowl for coupling the outer cowl to the combustor liner;  
       cutting between an outer surface and an inner surface of the inner cowl wherein the cut is formed upstream from a plurality of fastener openings formed within the inner cowl for coupling the outer cowl to the combustor liner;  
       removing the portion of the cowl assembly that is upstream from the cuts formed;  
       coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cuts formed, wherein the replacement cowl includes an inner annular portion, an outer annular portion, and a plurality of circumferentially-spaced radial ligaments extending therebetween; and  
       coupling the repaired cowl assembly to the combustor.  
     
     
       8. A method in accordance with  claim 7  wherein removing the portion of the cowl assembly that is upstream from the cuts formed comprises removing the wire-wrapped portion of the cowl assembly from the combustor. 
     
     
       9. A method in accordance with  claim 8  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cuts formed comprises coupling the replacement cowl assembly to the existing cowl assembly using at least one of a laser welding process and a brazing process. 
     
     
       10. A method in accordance with  claim 8  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cuts formed comprises coupling a replacement cowl to the existing cowl assembly that includes a variably selected amount of circumferentially-spaced radial ligaments to facilitate a pre-desired natural frequency during engine operations. 
     
     
       11. A method in accordance with  claim 8  wherein coupling a replacement cowl to the portion of the existing cowl assembly that is downstream from the cuts formed comprises coupling a replacement cowl to the existing cowl assembly to facilitate reducing high cycle fatigue induced to the combustor. 
     
     
       12. A method in accordance with  claim 8  further comprising inserting at least one fuel nozzle into an opening defined between adjacent circumferentially-spaced radial ligaments. 
     
     
       13. A method for replacing a portion of a deteriorated cowl assembly within a gas turbine engine combustor, the deteriorated cowl assembly including an inner surface, an outer surface, and a wire-wrapped portion, said method comprising: 
       cutting substantially radially through the deteriorated cowl assembly between the outer and inner surfaces of the deteriorated cowl assembly;  
       removing the wire-wrapped portion of the deteriorated cowl assembly that is upstream from the cut extended through the cowl assembly; and  
       coupling a replacement cowl onto the combustor to replace the portion of the deteriorated cowl assembly removed from the combustor, wherein the replacement cowl includes an inner annular portion and an outer annular portion that is substantially concentric with respect to the annular inner portion.  
     
     
       14. A method in accordance with  claim 13  wherein the combustor also includes a liner extending downstream from the cowl assembly, said method further comprising uncoupling the deteriorated cowl from the combustor by removing at least one fastener that is used to couple the cowl assembly to the liner. 
     
     
       15. A method in accordance with  claim 14  wherein coupling a replacement cowl onto the combustor to replace the portion of the deteriorated cowl assembly removed from the combustor comprises: 
       using a laser welding process to couple the replacement cowl to the existing cowl assembly; and  
       coupling the cowl assembly to the combustor liner using at least one fastener.  
     
     
       16. A method in accordance with  claim 14  wherein coupling a replacement cowl onto the combustor to replace the portion of the deteriorated cowl assembly removed from the combustor comprises: 
       brazing the replacement cowl to the existing cowl assembly; and  
       coupling the cowl assembly to the combustor liner using at least one fastener.  
     
     
       17. A method in accordance with  claim 14  wherein coupling a replacement cowl onto the combustor to replace the portion of the deteriorated cowl assembly removed from the combustor further comprises coupling a replacement cowl onto the combustor that includes a plurality of circumferentially-spaced radial ligaments extending between the inner and outer annular portions. 
     
     
       18. A method in accordance with  claim 17  wherein coupling a replacement cowl onto the combustor that includes a plurality of circumferentially-spaced radial ligaments further comprises coupling the replacement cowl to the combustor to facilitate a pre-desired natural frequency during engine operations. 
     
     
       19. A method in accordance with  claim 17  wherein coupling a replacement cowl onto the combustor that includes a plurality of circumferentially-spaced radial ligaments further comprises coupling the replacement cowl to the combustor to facilitate reducing high cycle fatigue induced to the combustor.